Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Case Reports
. 2016 Jul-Sep;11(3):317-8.
doi: 10.4103/1793-5482.148789.

Non psammomatous melanocytic schwannoma presenting as a subcutaneous nodule: A rare presentation of a rare lesion

Harveen Kaur Gulati  1 , Avinash R Joshi  1 , Mani Anand  1 , S D Deshmukh  1
Affiliations
Case Reports

Non psammomatous melanocytic schwannoma presenting as a subcutaneous nodule: A rare presentation of a rare lesion

Harveen Kaur Gulati et al. Asian J Neurosurg. 2016 Jul-Sep.

Abstract

Melanocytic schwannoma (MS) is an extremely rare soft tissue tumor accounting for less than 1% of all primitive nerve sheath tumors, with a predilection for spinal nerve involvement. To date, only 20 cases of cutaneous/subcutaneous MS have been described in literature. Here, we describe a case of MS presenting as a subcutaneous nodule in a 22-year-old male in right thigh. On examination, the nodule measured 2.5 × 2.0 × 1.5 cm with overlying skin showing a bluish hue and an ulcer. With a preoperative diagnosis of hemangioma, the patient was taken up for wide local excision and was diagnosed as a case of non psammomatous melanocytic schwannoma based on clinical, histological, and immunohistochemical studies. Immunohistochemistry revealed positivity with S-100, HMB-45, and Melan A with pericellular Laminin positivity. Carney's syndrome was ruled out. MS needs to be differentiated from other pigmented lesions like pigmented neurofibroma, Bednar tumor, cellular blue neavus, and especially malignant melanoma, which has an obvious ominous prognosis. Since MS can show unpredictable behavior especially in absence of overt malignant features, a long term follow up with or without radiotherapy is recommended.

Keywords: Carney's syndrome; laminin; malignant melanoma; melanotic schwannoma.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Photomicrograph showing (a) External surface of a wide local excision specimen with an overlying skin cover showing a bluish hue and an ulcer measuring 1.0×0.8cm; (b) Cut surface showing a jet black unencapsulated tumor with small tongue like projections in the surrounding tissue
Figure 2
Figure 2
Photomicrograph showing (a) Pigmented tumor over lined by epidermis along with native adnexal structures (H and E, ×100). (b) The deeper part showing the tumor arising from the nerve bundle on the left of photomicrograph (HandE, ×100)
Figure 3
Figure 3
Photomicrographs showing (a) Heavily pigmented tumor composed of hypercellular and hypocellular myxoid areas (H and E, ×100). The hypercellular areas showed; (b) Theques with pallisading of nuclei along with ganglion cells; (c) Spindle shaped cells arranged variably in long and short fascicles (H and E, ×400)
Figure 4
Figure 4
Photomicrograph showing (a) S-100 and (S-100, ×400); (b) HMB-45 (HMB-45, ×400) cytoplasmic immunopositivity
See this image and copyright information in PMC

References

    1. Hong-ying Z, Guang-hua Y, Hui-jiao C, Bing W, Qi K, Hua G, et al. Clinicopathological, immunohistochemical and ultrastructural study of 13 cases of melanotic schwannoma. Chinese Med J. 2005;118:1451–61. - PubMed
    1. Mees ST, Spieker T, Eltze E, Brockmann J, Senninger N, Bruewer M. Intrathoracic Psammomatous Melanotic Schwannoma associated with the Carney Complex. Ann Thorac Surg. 2008;86:657–60. - PubMed
    1. Küsters-Vandevelde HV, van Engen-van Grunsven IA, Küsters B, van Dijk MR, Groenen PJ, Wesseling P, et al. Improved discrimination of melanotic schwannoma from melanocytic lesions by combined morphological and GNAQ mutational analysis. Acta Neuropathol. 2010;120:755–64. - PMC - PubMed
    1. Kaehler KC, Russo PA, Katenkamp D, Kreusch T, Neuber K, Schwarz T, et al. Melanocytic schwannoma of the cutaneous and subcutaneous tissues: Three cases and a review of the literature. Melanoma Res. 2008;18:438–42. - PubMed
    1. Millar WG. A malignant melanotic tumour of ganglion cells arising from a thoracic sympathetic ganglion. J Pathol Bacteriol. 1932;35:351–7.

Publication types